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Aaron David Miller: NBC candidate forum documented the gulf in competence and understanding between Clinton, Trump

Trump's admiration for Putin and his disdain for US generals was notable, he says

Aaron David Miller is a vice president and distinguished scholar at the Woodrow Wilson International Center for Scholars and author of "The End of Greatness: Why America Can't Have (and Doesn't Want) Another Great President." Miller was a Middle East negotiator in Democratic and Republican administrations. Follow him on Twitter @aarondmiller2. The opinions expressed in this commentary are his.

(CNN)In the cruel and unforgiving foreign policy world of migraine headaches the next President is almost certain to inherit, which candidate would be better equipped to lead the nation?

And what did Wednesday night's battle of the would-be commander in chiefs tell us about their views on national security issues that we didn't already know? Here are some key takeaways.

Same old, same old

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Sure, time was short and it's hard to do justice to complex foreign policy issues in a rushed half hour per candidate format. Understandably most of the questions were focused on issues relating to veterans. But it's striking how many serious foreign policy issues weren't covered. Indeed, instead of asking tough questions on China, nuclear weapons, under what conditions would a candidate use force, NBC chose to play off the same thoroughly politicized and well-worn themes: support for the Iraq war and Clinton's emails. There was very little that was productive or new.

Those damn emails

Inevitably, the Clinton email issue was going to surface, particularly in a military audience familiar with classified material and the vigorous enforcement of the rules to protect it. Clinton admitted her mistakes in handling her emails, but her answers were lawyerly and technical and not the best way for her to have to open her segment. Indeed, the email issue in the forum was to some extent moderated by the fact that the two candidates weren't on the stage together and the discussion was courteous and relatively brief. That will definitely not be the case during the presidential debates.

Stealth policy on ISIS

Predictably, when asked about how he'd deal with ISIS, Donald Trump fell back on his new tack: That he'd ask the generals to develop a plan within 30 days about how to defeat and destroy ISIS. This formulation, accompanied by his traditional refrain that he wasn't going to telegraph his moves, contrasted sharply and negatively with Clinton's rather conventional but still comprehensive approach to fighting ISIS from the air, on the ground (though not with US combat forces), and in cyberspace. Indeed, when pressed by a vet to explain what he'd do after defeating ISIS, in the proverbial day after, Trump raised again the fantastical notion of seizing the Iraqi oil and leaving people behind to secure it.

Insulting the generals/Hurrah for Putin

For someone who prides himself on being pro-military, Trump did a number on the senior military command, at least those who served under Barack Obama. There was progression in his views in that he refrained from repeating his notion that he knows more about ISIS than the generals and that he would ask them to develop a plan. But his battering of the career military and his statement that those who worked on these issues in the Obama administration had been "reduced to rubble" was hardly the kind of sentiment that a commander in chief wants to engender in the military. Indeed, it's stunning to consider that Trump seemed more deferential and solicitous to Vladimir Putin (saying the Russian President has an 82% approval rating and that he's been a leader far more than our President) than he was prepared to be to President Obama.

Temperament/experience

Here is where the biggest gap appeared between the two candidates. It's not that Clinton was compelling or particularly charismatic. When asked what quality was most important to foreign policy leadership, Clinton replied that it was steadiness married to strength -- a compact response that seemed sensible and appropriate, particularly when compared to what Trump said. Asked by NBC's Matt Lauer what prepared him to make leadership decisions, Trump fell back on responses about building a great company, traveling around the world, dealing with China and having great judgment: "I called the shots." On balance, Clinton acted and sounded more serious and more presidential.

This was not a great night for either candidate. On substance very little was said that we haven't heard before with regard to policies. What the night demonstrated clearly, though, is that Trump is not comfortable with the substance of foreign policy issues, nor is he able to engage in detailed or even general conceptions of how to formulate policies.

What works so well in large and controlled rallies for Trump -- generalities and slogans -- doesn't work nearly as well in close-quarter verbal combat. Under the supervision of a fair and probing moderator and in direct exchanges between the candidates -- at least on foreign policy -- this may prove to be a real liability. At the same time, during a one on one face off with Trump, Clinton's emails may prove the same.